The present invention relates to a method of manufacturing a functional material thin film by introducing controlled radicals into a plasma, and also relates to a method of performing a plasma process for a functional material by a controlled plasma. The present invention also relates to a surface processing apparatus for processing a surface of a substrate by a controlled plasma. In the present specification, the term "surface processing apparatus" means both an apparatus for manufacturing a thin film on a surface of a substrate by a plasma chemical vapor deposition and an apparatus for processing or changing a surface condition of a substrate by a plasma etching.
Techniques for fabricating a functional material thin film and for working a functional material precisely have been widely used in manufacturing thin film electronic devices such as LSI, and would be indispensable technique for developing new materials or new devices, and performing a precision working for realizing integrated circuits. In the method of manufacturing thin films and the method of performing a precision process, a given reaction gas is introduced into a plasma to produce ions and radicals by decomposition or excitation of the introduced gas, and then the thus generated ions and radicals are reacted with a substrate having a surface to be processed. In this manner, a thin film is deposited on the surface of the substrate or the surface of the substrate is processed. In these methods, the radicals perform important role for realizing these processes.
In the formation of thin films of functional materials, production of new materials, precision process, radicals play an important role, and densities of radicals and compositions of radicals are determined in accordance with external conditions such as pressures of gases, kinds of gases, applied electric powers, sizes of process vessels and materials of process vessels.
Since radicals are neutral electrically, and thus its control is extremely difficult.
Therefore, by adjusting such external parameters, it is impossible to increase a density of given radicals in a plasma, said radicals playing an important role in the thin film formation and precision process. Furthermore, it is impossible to control precisely a density and a composition of desired radicals. Therefore, it is difficult to realize a remarkable improvement in the formation of thin films and precision process.
In the formation of thin films made of functional materials and precision process, a plurality kinds of gases are used and a plural kinds of radicals are produced by decomposition of these gases. In this case, production cross sections of these radicals have energy dependency, so that it is impossible to realize desired density and composition of radicals from a plurality of gases within an energy range of a plasma to be used.